Range finder for submarine and other periscopes



March l0, 1925.

Fig. 1.

15291225 STRANG RANGE FINDER FOR SUBMARINE AND OTHER PERISCOBES Filed June 17.1921

Figa.

Patented Mar. 10, 1925.

Unirse stares 1,529,225 PAiaN rN 'oF'Fliclzmrv JOHN MAETIN sTEANG, or GLAsGoW','soOTLAND, AssIGNOR To BAEEAND STEO'U'D, i' LIMITED, or GLASGOW, SCOTLAND.

RANGE FINDER EOE SUBMAEINE AND OTHER rEEIscoIEs.

Application filed June 17, 1921. Serial No. 478,305.'

To all whom t may concern:

Be 1tknown that I, JOHN MARTIN STRANG,

a subject of the King of Great- Britain and Ireland, and of Caxton Street, Anniesland, Glasgow, Scotland, have invented new and useful Improvements in Range Finders for Submarine and Other Periscopes, of which the following is a specica-tion.l

My invention refersfoto submarine and other periscopes, hereinafter and in the claims referred to generally as periscopes, of the type comprising a telescope system provided with at least two consecutive objectives` between which the beam is composed of parallel rays, and the object of my invention is to furnish periscopes of this type with improved means for the measurement of ranges which in operation are obtained from a known (or assumed) length at the target and a measurement of the angle subtended by this known length at the periscope. In the claims periscopes of this type will be referred to as periscopes of the type defined.

According to my invention I insert between two consecutive objectives of vthe telescope system of a periscope of the type defined a reiracting prisms system, in the path Y of a part, of the beam the rays of which are parallel and I provide means for imparting to the prisms of the systemv rotary movements whereby variable and adjustable deviation may be produced so that in the field viewed by an observer two images may be seen, one produced by rays which do not passl through the refracting prisms system,

the other by rays which pass through the refracting system, or a single image may be produced if the refractions produced in the prisms system nullify each other. For example, in one method according to my 1nvention I use a pair of equally refracting prisms of annular form and place them between two consecutive objectives, and for by the pair of prisms can be rotated 'together bodily. v

It will be clear that thetwo prisms, being of equal angle, in one position when theone prism isexactlyz` oppositely directed to.A the'Y other, the. eiiect will be that the two refaotions are opposite and annul onev another,

being zero. This position corresponds to the case where we get asingle image in the field of view without any' duplication.

If we requirey to measurea vertical angle the pair of prisms are' 1 rotated bodily to'-'v the angular indication o,f measur'ement then j gether till the` duplication of the image circular su'pport of each prism and drivei each prism by means of a pinion wheel. If the two shafts carrying these' pinion wheels are concentric to one another and parallel to the axis of the periscope, they may be led down below the bottom of the periscope case where a diiierential gear may be provided, one bevel wheel being fixed to the Outer shaft and the second bevel wheel to the inner shaft while the 'axis Voi.: the"` jockey wheel is provided with a drum or; disc upon which a' scale of angles is engraved. Ifthe axis of the jockey remains fixed a rotation of the drum or disc will produce duplication of the image in a particular direction,4 say, vertical, but if the axis of the jockey be* roi tated through any one or more revolutions or .fraction of a revolution about afvertical axis, the prism system will be rotated bodily together so that the'duplication, will now take place in a different direction, say, horizontally# f Instead of using concentric annular prisms, i. e., prisms in which circular holes` have been out, we mayfor example, use much smaller prisms placed opposite the central region of the objective and support these prisms on suitable glassplates, or by means of spiderlike holders. In this case the beam'of light to remain unrefrac'ted during the rotation of the prisms will be the annular portion meeting the objective.

- 0r again,l the two prisms may be unperforated and placed opposite about one half of the objective. j

I tation of the twoipr-isms and the bodily rol." tation of the two prisms together willlnow be given. 4Vie may providqt'eeth vr'o'fund the 'most telescopic system is designated 1, the' ure 1.

Examples of a few methods of carrying out this invention will now be described with reference to the accompanying drawing in which Figure 1 is a vertical section lower part of an ordinary periscope furnished with prisms and operating gear according to my invention. l

Figures 2 and 3 are vertical sections illustrating modifications of a portion of Fig- Figure 4 is a plan of the prism holder in Figure 3, while Figure 5 is a plan illustrating a modified arrangement of prism and another form of holder.

In Figure'l the objective of the lowerreflecting prism 2, and the eyepiece combination 3, 4, 5. The objective of the telescopic system next above the lowerinost is l. designated 6 and in accordance with this in- -`Atral circular holes 13 arranged concentrically4 with the axis of,"

j The upper pinion 15 is fixed to a shaft 17,\

`vention I place the refracting prisms between the objectives 1 and 6. In Figure 1 this mechanism consists of two annular refracting prisms 7 and S formed with cenand 14 provided and the objectives; The holders of these prisms are provided with teeth on the periphery engaging respectively with pinions 15 and 1()\.

which passes concentrically through a tubular shaft 18 to which 1G is fixed. Brackets 19 and 29 are provided for supporting shafts 17 and 18 from the periscope at the upper and lower ends respectively.

At the lower end of shaft 17 is lixed a bevel 20 and at the lower end of shaft 18 is fixed a bevel 21; a bevel 22 (carrying a graduated disc 23) gears with 2O and 21. Bevel 22 is mounted to rotate on a shaft 25. The shaft 25 is fixed to a piece 2G mounted to turn about the axis of the shaft 17 and caries a pointer 24 which forms an index whereby the graduated scale upon 23 may be read. If now disc 23 be turned by hand about shaft 25, the two prisms 7 and 8 are rotated in opposite directions so that the relative positions can be read olf at any time by the position of pointer 24 upon disc 23. ,lVe may suppose that the position shown in the figure corresponds to that suitable for measuring angles in a horizontal plane. I f now we desire to measure angles in a vertical plane, shaft 25 requires to bec turned about the axis of shaft 17 through the appropriate angle depending upon the ratio of the pitch diameters of 15 and 16 to the pitch diameters of the holders of the prisms 7 and 8. Thus, e. g., if this ratio is 1:4, it will be necessary to turn shaft 25 through just one revolution whereby the prisms are rotated bodily together from the position suitable for measurements in the horizontal plane to that required for operating in the through the .i

" telescope system,

vertical plane after which, for the measurement of angle, the prisms are rotated equally in opposite directions. i

In Figure 2, the concentric annular prisms are replaced by circular and much smaller prisms 9 and 10 placed opposite the centralv region of the objective and glass plates 31 and 32 respectively.

In Figure 3, these prisms are supported by a' spider-like frame l1 seen in plan in Figure 4.

Figure 5 shows a plan of a modification in which the prisms are placed opposite a portion of one side of the objective, one prism 12 only being seen in this view. v

I claim 1 l. A periscope of the type comprising telescope system, two consecutive objectives in the telescope system, a refracting prisms system comprising two annular prisms situated between the two consecutive objectives in the path of part of the beam and arranged with their central holes concentric to the axis of the objectives and means for imparting to the prisms of the system rotary movements for obtaining the measurement of angles. i 1 i Y j 2. A periscope of the type comprising a two consecutive objectives in the telescope system, a refracting prisms system comprising two equally refracting pirisms of annular form situated between the two lconsecutive objectives in the path of part"of the beam and arranged with their central holes concentric to the axis of the objectives and means for impartingto the supported on prisms of the system equal and opposite roof the system together bodily, for the pur-Y poses set forth.

L1.' A periscope of the type coinprisiug a` telescope system, two consecutive objectives in the telescope system, a refracting prisms system comprising two equally refracting prisms situated between the two consecutive objectives, means for imparting to the prisms of the system equal and opposite rotary movements for obtaining the measurement of angles, and means for rotating the prisms of the system together bodily, for the purposes set forth.

5. A periscope of the type comprising a telescope system, two consecutive objectives in the telescope system, a refracting prisms system comprising two annular prisms situated between the two consecutive objectives Cil wmf'

and arranged with their central holes concentric to the axis of the objectives, ine-ans for imparting to the prisms of the system relative rotary movements tor obtaining the measurement ot' angles, and means for' rotating the prisms of the system together bodily, for the purposes set forth.

l6. A periseope of the type comprising a telescope system, two consecutive objectives in the telescope system, a refracting prisms system comprising two equally retraoting prisms of annular form situated between the two consecutive objectives and arranged with their central holes concentric to the axis of the objectives, means for imparting to the prisms of the system equal and opposite rotary movements tor obtaining the measurement of angles, and means for rotating the prisms ot' the system together bodily, for the purposes set forth.

7. A periscope of the type comprising a telescope system, two consecutive objectives in the telescope system, a refraoting prisms system comprising two reti-acting prisms situated between the two consecutive 0bjeetives, two holders one for each prism, gear teeth on the periphery of each holder, two pinions gearing one with each holder, two shafts one for each pinion, and means for imparting to the shafts rotary movements, for the purposes set forth.

S. A periseope of the type comprising a. telescope system, two consecutive objectives in the telescope system, a refracting prisms system comprising two refracting prisms situated between the two consecutive objectives, two holders one tor each prism, gear teeth on the periphery ot each holder, two pinions gearing one with each holder, two shafts one for each pinion, ditt'erential gear for operating the shafts associated with a graduated disc and pointer, for the purposes set forth.

J OH N MARTIN j STRANG. 

